Evolutionblog

Commentary on developments in the endless dispute between evolution and creationism.

Wednesday, April 09, 2003

On Interpreting Evidence From the good folks at the pro-Intelligent-Design website Access Research Network comes the following advice on properly interpreting evidence:

"A parallel can be made to Darwinian evolution, as it often embraces multiple competing outcomes and then interprets any evidence as support for the theory. One example would be the two-horse race of explaining biological order. If what we see is exquisite, then we are reminded of the degree of fine-tuning that the selection/mutation mechanism can reach when given enough time, but if there appears to be a flaw or if the form seems crude, then we are reminded that we are working with a blind and purposeless mechanism - after all what can we expect? Armed with both explanations, every possible outcome has been successfully accounted for and so nothing appears surprising. Is there any doubt, then, why you never hear a Darwinian say; “Now if I saw that, I’d know it was designed”? Design conclusions are ruled out ahead of time by putting a Darwinian bet on every horse." -Paul Nesselroade, "Betting on All the Horses".

This is a curious criticism coming from an ID theorist. After all, they are the ones who point to the beauty and perfection of nature as evidence of a designer, but interpret flawed or crude designs as evidence only of the inscrutibility of the designer's motives.

Leaving this aside, the criticism is not valid even taken on its own terms. It is a simple logical consequence of the nature of natural selection that under certain conditions it can explain organs of great perfection, and in other situations can produce vastly imperfect structures. That is not the fault of biologists. But the fact remains that there are severe limits to the kinds of structures and behaviors that can be attributed to natural selection. For example, any trait that existed solely for the benfit of members of another species could not be explained by selection. Similarly, any complex structure whose parts can not be indentified as arising from simpler structures that were common in the organism's lineage, possible for other purposes, would also be hard to explain.

Furthermore, scientists do not use natural selection as a mystical incantation they can use to dispell any biological mystery. Instead, it is used as a way of generating testable hypotheses about the history of the structure. Examples of this are ubiquitous in the professional literature of evolutionary biology.

Biologists routinely points to biological structures and say, "That structure was not crafted by natural selection." The recent discovery that lateral gene transfer is an important mode of evolutionary change in prokaryotes is just one example of this. But Nesselroade, like all of the prominent ID theorists, does not care about the actual state of modern biological research. His job is to produce plausible sounding rhetoric. Truth be damned.

Tuesday, April 08, 2003

Crank Alert II "Although the postmodern era questions everything else—the possibility of knowledge, basic morality and reality itself—critical discussion of Darwin is taboo. While evolutionary biologists test Darwin’s hypothesis in every experiment they conduct, the basic premise of evolution remains an [sic] scientific Holy of Holies, despite our absurd skepticism in other areas....Biologists continue to recite the worn credo, “the central, unifying principle of biology is the theory of evolution.” But where would physics be if Einstein had been forced to chant, “the central, unifying principle of physics is Newtonian theory,” until he could not see beyond its limitations?" -Richard Halvorson, Confessions of a Skeptic, The Harvard Crimson.

Crank Alert I "It may well be the most important intellectual movement to occur in the last 200 years, if not the last half-millennium. Its roots are in the sciences, but when it reaches full flower, it may branch into nearly every discipline, from theology, philosophy, and the social sciences to history and literature, and redefine almost every aspect of culture, from morality and law to the arts.

It’s the Intelligent Design (ID) movement, and it’s reshaping the face of science." -Benjamin Wiker, Does Science Point to God, Crisis magazine.

Monday, April 07, 2003

Probably a Bad Idea... It seems that Lake Austin in Texas is suffering from an infestation of Hydrilla, a non-native plant species that got introduced into Florida waterways many years ago and has been spreading around the country ever since. The weed grows very quickly, can regenerate itself even from a tiny piece of stem, and sends up long, wispy tentacles that clog boat motors and are generally unattractive. Now the good people in Texas are introducing another non-native species, the grass-eating carp, into their lake. These fish can grow up to 400 pounds and are completely vegetarian. The hope is that they will keep the Hydrilla population under control.

Critics point out that the carp eat all sorts of vegetation, and will quickly pick the lake clean of all vegetation. This will cause irreparable harm to other fish species, especially the bass population that makes the lake such a popular fishing spot. Supporters, so disgusted with the pernicious effect of Hydrilla respond, basically, "Fuck the bass!" The details are available from The New York Timeshere.

School Board Watch The good folks in Blount County, Tennessee have voted to reject three biology textbooks on the grounds that they discuss evolution but not creationism. The board voted 2-1, with four board members abstaining. Talk about your profiles in courage.

In this article from the Daily News of Maryville, TN, it is pointed out that the three books in question had been chosen by the biology teachers of the local high schools. In a typical bit of school board arrogance, the board substituted their judgment for that of the teachers.